There are good reasons why we don't see a lot of gastropods as protagonists in family movies.

-- Snails don't have hands or feet, limiting an animator to just eye and mouth movements for expressiveness.

-- Snails are pests that interfere with the human food chain, resulting in a take-it-or-leave-it approach to rooting for their survival.

-- If they come in contact with salt, you're looking at an immediate PG-13 rating.

The makers of "Turbo" give the snail-competing-in-the-Indy-500 genre a hell of a try. The animated adventure has some of the stranger moments of the summer movie season - and that's after Russell Crowe saddled up a giant dragonfly in "Man of Steel."

But after the originality of the hero, the filmmakers borrow too heavily from other movies; the similarities to "Ratatouille" and "Cars" are almost distracting. The "Turbo" mantra of "No dream is too big, no dreamer is too small" could apply to at least half of the kid-friendly films released in the last year. There are too many characters and too much action, as if the filmmakers couldn't trust their young audience to stay focused on the story.

Turbo (voiced by Ryan Reynolds) is a snail who wants to go fast; the Ricky Bobby of garden pests. The early scenes of snails harvesting a tomato garden have an appropriately unnerving quality. One surprise among the three screenwriters is "The Wrestler" and "Big Fan" scribe Robert D. Siegel. (We're guessing he was behind the running joke where a bird swoops in and ruthlessly snatches up hapless snails at random intervals.)

After the happy accident involving a nitrous oxide bath that gives Theo near-unlimited speed, the snail befriends two human brothers working out of a taco truck, who have a makeshift family (and potential sponsors) in their strip mall neighbors. A team of hot-rod-racing snails shows up, presumably as an excuse to add Snoop Dogg and Samuel L. Jackson to the voice cast. And because we need a bad guy - and why not make him French? - elite racer Guy Gagne (voiced by Bill Hader) tries to crush the racing snail.

"Turbo" comes from DreamWorks Animation, which is developing a reputation for memorably offbeat characters. From the super villain with a heart of gold in "Megamind" to "The Penguins of Madagascar," the films have a subversive streak, but also a core of plaintive sensitivity. Taco moguls Angelo (Luis Guzman) and Tito (Michael Pena) are the most fully formed characters, struggling with their business but remaining unconditionally loyal to each other. Even if you don't care about the snails, you want good things to happen to them.

The movie is so derivative in so many ways that you'll start to think the nods are on purpose. When Turbo's human friends show up as the pit crew, they're wearing T-shirts with the exact same typeface as the Cutters in "Breaking Away."

The intended preteen target demographic for "Turbo" will not question the logic of a snail being allowed in the Indy 500, so we'll try not to spoil the fun. But it's worth noting that "Cars" looks like a Ken Burns documentary next to this film. Five hundred laps and not a single car thought to crush the snail under a tire?

For the sequel, we'd also like to see Ortho Pest Control as a sponsor.